Optical processing is of interest because free space optics can be used to connect two dimensional arrays of optical devices or circuits for parallel processing. Parallel processing so accomplished will, it is hoped, offer capabilities due to its massive connectivity which are not readily available in a purely electronic system. Some contemplated optical devices or circuits, which may be useful in such arrays, require connections for electrical signals to the individual optical devices or circuits.
For small arrays, the number of individual devices is small and each device can be electrically contacted individually with relative ease. For example, consider a 4.times.4 array which has a total of 16 individual devices and requires only 16 electrical connections. However, a 32.times.32 array would require at least 1024 electrical connections. While such a large number of electrical connections can be made with present technology, still larger arrays are contemplated and will require even more electrical connections. The number of connections required for such arrays will be prohibitively large for individual connections to devices to be made practically.
While individual connections to devices are desirable because they permit the entire array to be reconfigured in a single cycle, a matrix addressing scheme would reduce the number of electrical connections required although the array reconfiguration time might be increased. In a matrix addressing scheme, devices are addressed by row and column. For example, consider a 64.times.64 array of devices. A matrix addressing scheme would require only 128 electrical connections while 4096 connections would be required if the devices were contacted individually. The entire array will require 64 cycles for reconfiguration, and the array must have some form of memory mechanism during reconfiguration.
An attractive device for use in an array of optical devices is termed the S-SEED. The term is an acronym for symmetric self-electro optic effect device. The device has two reversed biased p-i-n diodes connected in series with the i-region of the diode having at least one quantum well. Each diode acts as the load for the other diode. The device relies upon the quantum confined Stark effect (QCSE) for its operation. S-SEEDs, which are now well known to those skilled in the art, have many attractive features such as optical bistability, cascadability, three-terminal operation, and small switching energies. See, for example, Applied Physics Letters, 57, pp. 1843-1845, Oct. 29, 1990, for a description of S-SEEDs.
However, electrical matrix addressing schemes for S-SEEDs which exhibit optical bistability have not been implemented. A matrix addressing scheme can not be implemented with only two connections to the S-SEED; i.e., with only connections to the outer nodes of the series connected diode pair.